Fix the extension trace.so for RHEL7.6 ,which moved
ftrace_event_call.data into an anonymous union,and the
previous offset has changed, so the trace.so extension
module fails to load ,indicating "no commands registered:
shared object unloaded".
---
extensions/trace.c | 20 ++++++++++++++++++--
1 file changed, 18 insertions(+), 2 deletions(-)
diff --git a/extensions/trace.c b/extensions/trace.c
index 7d76699..ad71951 100644
--- a/extensions/trace.c
+++ b/extensions/trace.c
@@ -853,8 +853,18 @@ static int syscall_get_enter_fields(ulong call, ulong *fields)
inited = 1;
data_offset = MAX(MEMBER_OFFSET("ftrace_event_call", "data"),
MEMBER_OFFSET("trace_event_call", "data"));
- if (data_offset < 0)
- return -1;
+ if (data_offset < 0) {
+ /*
+ * rhel-7.6 moved the .data member into an anonymous union.
+ */
+ if (MEMBER_EXISTS("ftrace_event_call", "rh_data") &&
+ MEMBER_EXISTS("ftrace_event_data", "data")) {
+ data_offset = MEMBER_OFFSET("ftrace_event_call", "rh_data") +
+ MEMBER_OFFSET("ftrace_event_data", "data");
+ inited = 2;
+ } else
+ return -1;
+ }
enter_fields_offset = MEMBER_OFFSET("syscall_metadata", "enter_fields");
if (enter_fields_offset < 0)
@@ -868,6 +878,12 @@ work:
"read ftrace_event_call data", RETURN_ON_ERROR))
return -1;
+ if (inited == 2) {
+ if (!readmem(metadata, KVADDR, &metadata, sizeof(metadata),
+ "read ftrace_event_call data (indirect rh_data)", RETURN_ON_ERROR))
+ return -1;
+ }
+
*fields = metadata + enter_fields_offset;
return 0;
}
--
2.17.1
--
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